Alternating field activated carbon fluidized bed electrode for water disinfection

Zoetwaterschaarste is een groot probleem voor de volksgezondheid. Ongeveer 10 % van de wereldbevolking heeft geen toegang tot veilig drinkwater en 36 % van de bevolking heeft geen basis sanitaire voorzieningen. Het grootste deel van deze mensen leeft in waterschaarse gebieden en hergebruik van water is relevant om te voorzien in de benodigde hoeveelheid zoet water. Om meer water te hergebruiken zou behandeld afvalwater gebruikt kunnen worden voor bijvoorbeeld irrigatie. Disinfectie van hergebruikt afvalwater is dan belangrijk om de veiligheid van mens en dier te waarborgen. Een mogelijke alternatieve manier van desinfectie is gebaseerd op het gebruik van elektrische velden. Sterke elektrische velden (bijvoorbeeld als gepulseerde elektrische velden) voor desinfectie van water worden al enige decennia toegepast. Echter, deze technologie maakt gebruik van een sterk elektrisch veld, wat problematisch is voor troebel water die veel organische stof bevatten. Dit kan worden vermeden door gebruik te maken van een zwak, wisselend elektrisch veld gecombineerd met een gefluïdiseerd bed elektrode (FBE) van granulaire actieve kool (GAC). Het doel van dit proefschrift is om het principe aan te tonen van deze FBE desinfectietechnologie en om de belangrijkste componenten van het onderliggende mechanisme te beschrijven

pH effect on decolorization of raw textile wastewater polluted with reactive dyes by advanced oxidation with uv/h2o2

The effectiveness of the advanced oxidation process (UV/H2O2) in decolorizing real textile wastewater polluted with commercial reactive dyes - Reactive Yellow 84 and Reactive Red 141 was investigated. All the experiments were performed in a lab-scale reactor with the original high pH of the wastewater. The dyeing wastewater was decolorized in 5 hours. After its acidification to pH 3 the decolorization process was more efficient. Full decolorization was then achieved in 2 hours and the decrease in COD exceeded 70%. The reaction rate constants obtained were as follows: at pH 11.4, 0.0065 min(-1); at pH 7, 0.0044 min(-1), and at pH 3, 0.019 min(-1), which testified to pH importance for UV/H2O2 oxidation process

Apparatus and method for purifying a fluid

The present invention relates to a device and method for purifying a fluid such as an aqueous liquid flow. The purifying device herein comprises: - a container for the fluid; - electrodes placed in the container and operatively connected to an alternating current source; and - an ultrasonic wave generator placed in the container

Alternating electric field fluidized bed disinfection performance with different types of granular activated carbon

The removal of pathogens from effluents is important to promote the reuse of these water resources and safeguarding human health, especially in water scarce areas worldwide. Previously a proof-of-principle of a method for water disinfection consisting of fluidized bed electrodes (FBE) with RX3 EXTRA granular activated carbon (GAC) and a low strength alternating electric field (AC field) in radio frequency range (80–200 kHz) was published. In the study presented here we investigated the mechanistic role of 10 different types of GAC in radio frequency FBE disinfection with Escherichiacoli YMc10 as the model microorganism. The disinfection performances with only GAC, and GAC combined with an AC field were quantified. Seven GACs showed poor to intermediate and three GACs (Norit RB3 (2.7 Log CFU E. coli decrease), Sorbonorit 3 (2.8 Log CFU E. coli decrease) and RX3 EXTRA (3.4 Log CFU E. coli decrease)) showed substantial disinfection in FBE. The results suggest a relation between the pHpzc of the GAC and the disinfection performance. Disinfection performance increased with bigger particle size and decreasing conductivity of tested GACs. We conclude that these physico-chemical and physical properties of GAC are important factors controlling the disinfection performance of these type FBE systems

Alternating electric fields combined with activated carbon for disinfection of Gram negative and Gram positive bacteria in fluidized bed electrode system

Strong electric fields for disinfection of wastewaters have been employed already for several decades. An innovative approach combining low strength (7 V/cm) alternating electric fields with a granular activated carbon fluidized bed electrode (FBE) for disinfection was presented recently. For disinfection performance of FBE several pure microbial cultures were tested: Bacillus subtilis, Bacillus subtilis subsp. subtilis, Enterococcus faecalis as representatives from Gram positive bacteria and Erwinia carotovora, Pseudomonas luteola, Pseudomonas fluorescens and Escherichia coli YMc10 as representatives from Gram negative bacteria. The alternating electric field amplitude and shape were kept constant. Only the effect of alternating electric field frequency on disinfection performance was investigated. From the bacteria tested, the Gram negative strains were more susceptible and the Gram positive microorganisms were more resistant to FBE disinfection. The collected data indicate that the efficiency of disinfection is frequency and strain dependent. During 6 h of disinfection, the decrease above 2 Log units was achieved with P. luteola and E. coli at 10 kHz and at dual frequency shift keying (FSK) modulated signal with frequencies of 10 kHz and 140 kHz. FBE technology appears to offer a new way for selective bacterial disinfection, however further optimizations are needed on treatment duration, and energy input, to improve effectiveness

Combining fluidized activated carbon with weak alternating electric fields for disinfection

This study presents fluidized bed electrodes as a new device for disinfection. In the fluidized bed electrodes system, granular activated carbon particles were suspended, and an alternating radio frequency electric field was applied over the suspended bed. Proof-of-principle studies with the luminescent non-pathogenic bacterium Escherichia coli YMc10 demonstrated that disinfection with fluidized bed electrodes requires both the presence of granular activated carbon particles and the application of radio frequency electric field. Disinfection was investigated at various frequencies in range from 80 to 200 kHz at electric field strength of 6 ± 0.5 V/cm during 6 h. The largest decrease of E. coli viable cell concentration in the liquid (from 108 to 106 CFU/mL) was obtained at an optimum frequency of 140 kHz. Possible mechanisms of this electromediated disinfection are discussed in the manuscript. The results are promising for development of a new disinfection process with fluidized bed electrodes